According to a report this month from the Soufan Group, these are the estimated minimum number of foreign fighters in Syria and Iraq by country of origin.

It is estimated that over 20,000 foreign fighters have travelled to Iraq and Syria since fighting broke out in 2011.

While there are no confirmed figures for the official tally, experts predict that many are still fighting in the conflict zone - while a significant proportion have travelled home.

Already more have travelled to the region than the total who traveled to Afghanistan during its ten-year war.

As well as the Islamic State (also known as Isil and Isis), which is attracting increasing numbers to its cause, there are several other factions fighting in Iraq and Syria.

The foreign fighters joining these groups are from at least 81 countries - a quarter of which have no reported quantity of fighters.

There are approximately 5,000 people from Europe - with the most fighters leaving France, Germany and the UK.

The UK has seen an estimated 700 jihadists travel to Syria and Iraq. Some estimates say that half of these have returned to the UK, while 50 are reported to have died.

The Asian continent has seen the most citizens travel to Syria and Iraq, with over 11,000 people estimated to be in the conflict zone.

The countries with the most fighters in the conflict are Tunisia, Saudi Arabia, Jordan, Russia and France.

While around 5,000 Tunisians are reported to be fighting in Iraq and Syria, a further 5,000 have been stopped from leaving the country before they could join the fighting.

It can be assumed that the majority of the people who have travelled are with the Islamic State, according to the Soufan Group that collates the figures.

The group said that the figures may include women and children, who usually do not fight in the conflict. There are also unreported numbers of people who have died in or returned from the conflict zone.

While national governments do not know precise counts of their nationals who have gone to fight, estimates have been gathered by the United Nations, the Soufan Group and the International Centre for the Study of Radicalisation.